Another problem with your $2,600 BTC price prognostication for late 2019 or 2020, jonoiv, relates to a kind of presumption that you seem to have concerning what kind of market BTC currently is in.  

In other words, until further notice, there seems to be pretty decent odds that we have already transitioned into a bull market; therefore, a breaking of the BTC price upwardly seems to be more likely than breaking of the BTC price down.  So, it seems that you are presuming the extra-ordinary when you are asserting down, with such certainty.

Another way of saying it is that a lot of changes in BTC price dynamics is going to have to happen in order for BTC's current price trend to change direction, including a real need to break down to below $6k - which seems quite reluctant to happen at this time.  

Furthermore, even a break of the BTC price down to below $6k would not seem to be a significant condition precedent to take BTC out of our currently existing bull market leaning.

Surely, I am receptive to change my perspective about what kind of market we are currently in, and surely, I have not been the type to be buying BTC on the way up in anticipation of a kind of inevitable and continued UP..

Nonetheless... Odds of UP seem to continue to be better than Odds of down, even if we were to have some shorter term correction in the interim, such as going down to $6k-ish.  So, yeah, even refilling your BTC bags in the $6k price arena comes off as 50/50 at best.. .. and I would not want to be betting any more than 50% of my BTC stash on something that has in the ballpark of merely 50% odds.